Over these past 20 years, it has become an annual rite of summer: the massive propane grills, 500 pounds of John Vaccaro’s homemade sausage, free ice cream, and rented port-a-potties on the driveway of 102 Chesterfield St.

Each year on July 12, Mayor Thomas M. Menino has hosted a sprawling block party outside his house in Readville, a sleepy and almost suburban neighborhood in the far reaches of Boston. The festival started in 1993, the day he became acting mayor. It was like a homecoming parade to mark a local boy’s ascension at City Hall, an Italian triumph in a city long dominated by the Irish.

But this year was different. The party Friday marked Menino’s 20th anniversary of taking the oath. And because Menino is not running for reelection, scores of political candidates buzzed through the crowd, including almost all of the dozen people hoping to replace the host.

“I was going to go to the [Democratic] convention tonight in Lowell,” said Jennifer Springer, a union organizer wearing a black cocktail dress. “But this is the place to be.”

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Some partygoers played “candidate bingo,” checking names off printed sheets of paper when they spotted a candidate. Seasoned political operatives who have yet to join a mayoral campaign avoided making eye contact with candidates, looking down as they waited for sausages.

Menino stood at the end of his driveway, leaning on a cane, and posing for photographs with constituents. A crowd formed around the mayor like a receiving line at a wedding. A group of women sat on his front porch eating ice cream.

Menino paid for the event out of his political campaign account, which has been shrinking since the start of the year but still had a balance of $515,000 at the end of June. No city money is spent on the block parties, according to Menino’s spokeswoman, Dot Joyce.

Records from Menino’s fund-raising account showed several expenditures for the block party: $30 for a temporary city permit to serve food, $900 for face painting, and $2,000 for ice cream. This year, they hired two ice cream trucks. Last year, there was only one and the line was interminable.

Hours before the cookout started, neighbors arrived by foot, many with the aid of canes and walkers and carrying lawn chairs. Inside his house, Menino sat in his well-worn maroon recliner wearing gym shorts from a physical therapy session. He thought about the first block party, when Vaccaro brought 350 pounds of sausage and the stereo played the Frank Sinatra song “My Way.”

“Some days, it feels like a long time,” Menino said. “Some days, it feels like it came very quickly.”

That day 20 years ago was not without drama. Rumors swirled that Mayor Raymond L. Flynn might push back his resignation. Menino — then City Council president and poised to take over — waited anxiously in his City Council office when somebody burst in the door.

“Hooray!” Menino remembered the person yelling. “Flynn passed the papers to the city clerk!”

Menino then walked across the fifth floor of City Hall to the mayor’s office and took the oath. Flynn left City Hall in a police motorcade, speeding to Logan Airport, where he flew to Washington to begin life as US ambassador to the Vatican.

Menino walked behind the big desk in the mayor’s office. He sat down in the chair.

“They will need a crane to get me out of this chair,” Menino said, according to aides.

In four months, Menino would win his first mayoral election, a feat he would repeat four more times. Every summer on July 12, Menino held the block party to commemorate that first day.

Vaccaro, the 88-year-old who supplies the sausage, was not ready for Friday to be the last cookout.